If the iPad is subscribed to a feed, there are 299 new episodes that you have not listened to. They are probably on the podcast server. Though your settings may determine there are 1 or more episodes downloaded to the iPad. Probably not more than 5. You would not have the space for 299 episodes on an old iPad.

If you sync with iTunes that is also subscribed to the same podcasts, iTunes can inform the iPad how many you have listened to on other devices and drop that number. Or you can remove the subscription from the iPad.

Have you backed up your iTunes Library this week? If not, you are risking losing your music and playlists....